/Engine/Source/Runtime/Engine/Classes/GameFramework/GameModeBase.h
Used to swap a viewport/connection's PlayerControllers when seamless traveling and the new GameMode's controller class is different than the previous includes network handling
virtual void SwapPlayerControllers ( [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) * OldPC, [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) * NewPC )